Oral Contrast-enhanced Helical CT Cholangiography And Its Clinical Application

Objective:To probe the key points of oral contrast-enhanced helical CT cholangiography(OCHCTC)technique, and assess its feasibility and clinical application.Materials and methods:Thirsty-six healthy volunteers were random divided into two groups and ingested 3g and 6g iopanoic acid respectively. 26 patients suspected bile diseases were ingested 6g iopanoic acid. Subjects were undergoing helical CT scanning 12,14hr after iopanoic acid administration and oral fat-meal. Three-dimensional and two-dimensional reformations were generated from a set of axial source images. Two radiologists independently interpreted the helical CT cholangiograms. In all patients, findings from CT cholangiography were compared with those from ultrasonography, ERCP, surgery, pathology and clinical pursued. The effect of time ,dose and serum bilirubin levels on biliary opacification was observed. The Student t tests were applied .Results:(1) The oral contrast agent was well tolerated. Three had nausea and one had vomiting in nine volunteers who had mild diarrhea. Only two persons had diarrhea in group 3g. 6 patients had diarrhea. The total rate of diarrhea is 24.2% .(2)The scan interval has no effect on the reinforcement of liver parenchyma, but the dose of iopanoic acid does(P<0.05). Group 6g are greater than group 3g. (3) The biliary attenuation in group 6g are greater than group 3g. It has statistical difference(P<0.05).(4) The biliary opacification of group 12h and 14h ,which were not statistical difference , is less than group fat-meal.Any one of group 12h or 14h has statistical difference with groupfat-meal(P<0.01). The biliary opacification of group 6g of volunteers has not statistical difference with group patient who also ingested 6g iopanoic acid in 12h or 14h. (5) The grade of anatomic visualization of the biliary tree in group 6g are greater than 3g(P<0.05).Group 12h and 14h, 14h and fat-meal haven't statistical difference(P>0.05), but group 12h has statistical difference with group fat-meal(P<0.05). (6) The grade of anatomic visualization of the biliary tree in group 12h, 14h of volunteers and all groups of patients are statistically significant positive correlation to the opacified bile(P<0.05). But the correlation was not proved on group fat-meal of volunteers(P>0.05). (7)There is a statistically significant negative correlation between attenuation of bile and serum bilirubin level, which is less than 4.0mg/dL.The biliary opacifications , which serum bilirubin level is greater than 4.0mg/dL, were mild or no opacification. (8) The degree of biliary opacification was sufficient to perform three-dimensional and two-dimensional reconstructions in all volunteers and 23 patients (88.5%). Compared with the axial source images, 3D images revealed the bile duct and its lesions more directly. Conclusion:OCHCTC is a safe, feasible, reliable and noninvasive method for revealing biliary anatomy. 3D images revealed biliary anatomy and the lesions, which provide plentiful morphologic information to the diagnosis and differential diagnosis of biliary dieases. It enhanced diagnostic ability of biliary diseases and may play a role in clinic.